An orthopedic cast is used to protect and immobilize a portion of the human body. Often, an orthopedic cast is applied following a procedure to set one or more broken bones. In such cases, the portion of the body with the broken bone is encased in the orthopedic cast, holding the bone fragments in place so that the bone can heal. Other names by which an orthopedic cast is commonly known include a surgical cast, or often simply a cast.
The orthopedic cast is formed by wrapping cotton strips saturated with wet plaster of paris around the portion of the body with the broken bone. When the wet plaster dries, the hardened cast is formed. Other techniques or materials for constructing the cast are available, such as the use of thermoplastic- or fiberglass-infused bandages, but irrespective of the construction the desired end result is a hard shell about a limb or other portion of the human body that immobilizes and protects in order for a broken bone to heal. Casts can be used for conditions other than broken bones as well, including following repair of ligaments or other structures in the body.
Casts come in a variety of shapes. They may cover only a portion of a limb, or they can cover a larger portion of the body. For example, a spica cast is a cast which surrounds the trunk of the body and one or more limbs, and a hip spica cast is a cast surrounding the trunk of the body and one or both legs. Larger casts such as the hip spica are used, for example, where there has been a complex fracture requiring extensive surgery, or following surgery on a child to remedy a congenital dislocation of the hip. Other conditions requiring a larger cast, such as a spica cast, during healing are known.
In instances where an extensive surgery to repair a complex break or a congenital dislocation is required, it is often desirable to continue anesthesia to the patient following the surgery. Following the surgery and once the patient has awakened from the general anesthesia, a continuous infusion of local anesthesia to the area operated on can be delivered for post-operative pain relief. This technique is advantageous because it offers more granular control of pain, while reducing exposure to narcotic pain-killers and their side effects. The local anesthesia is delivered post-operatively utilizing the same nerve catheter used to numb the operative area during the surgery.
An issue can arise when the cast covering the operative area is fabricated, however, as the cast must also cover the site of the passage of the catheter into the body, where the catheter enters the body tissue. Once the cast hardens, the lumen of the catheter runs underneath the cast to the edge where it exits the cast. The site where the catheter enters the body, however, is completely covered underneath the hardened cast.
Covering the portion of the catheter that enters the body with the cast means that the site where the catheter enters the body can not be viewed during the post-operative delivery of anesthesia. Any visual indications of infection at the site are invisible. Additionally, if the anesthesia does not seem to be working well, there is no way to tell whether the catheter has become dislodged. Finally, at the end of hospitalization and before the patient goes home, it is difficult to remove the catheter, being buried under the cast.
What is needed is a manner of leaving a channel in a cast when the cast is fabricated. Such a channel would permit viewing of the site where the catheter enters the body tissue to enable a visual check for infections or dislodgment of the catheter. The channel would also permit easy access to the catheter for removal prior to the patient being sent home.
The cast and channel would be formed around the very nerve catheter inserted pre-operatively for local anesthesia, allowing the catheter to remain in place throughout the surgery, construction of the cast, and subsequent post-operative recovery. Such a channel could also be used for other devices or tubes which would be desirable to run through, rather than underneath, a cast. These other devices or tubes that could run through a channel in the cast might include a pre-existing drain or feeding tube, among other possibilities. But for the greatest structural integrity of the cast, the channel through the cast would need to be as small as possible.
Accordingly, this application discloses systems and methods for providing a channel through an orthopedic cast.